Electrical furnace



R. S. WlLE.

ELECTRICAL FURNACE.

APPLICATION FILED FEB. 26. 1920.

1,345,976. at t d July 6, 1920.

2 SHEETS-SHEET I.

5y /7/8 flfforney UNITED STATES RAYMOND SAMUEL WILE, or NEW YORK, 1v. Y.

ELECTRICAL FURNACE.

Specification of Letters Patent.

Patented July 6, 1920.

Application filed February 26, 1920. Serial no. 361,379.

To allwhom it may concern:

Be it known that I, RAYMOND SAMUEL VILE, a citizen of the United Statesof America, residing at 884 Riverside Drive, New York, in the county ofNew York and State of New York, have invented certain new and usefulImprovements in Electrical Furnaces, of which the following is aspecification.

This invention relates to improvements in electrical furnaces and moreparticularly to the type of electrical furnace which is designed formelting gold, silver and the like in. crucibles as well as for heattreating steel tools and other like heating purposes. I

More especially the invention relates to a novel resister arrangement ina furnace of this character.

One of the important objects of this invention is to provide a novelarrangement of the resisters to effect a concentration of the heat nearthe center of the furnace.

Another of the important objects of the invention is to provide animproved form of resister element adapted to form, with other likeelements and the terminals of the furnace, a hollow cylinder.

A third important object of the inventio is to so form resister elementsthat, when the elements are combined, the current flow producing heatingof said elements will be greater nearer the center of the furnace thantoward the exterior of said furnace.

A fourthimportant object of this invention is to provide, in combinationwith an electric furnace, a transformer arranged to afford a range ofvoltages for the furnace so that the current of the furnace may becontrolled within wide limits and thereby an extreme flexibilityattained in the temperature control.

With the above and other objects in view, as will be hereinafterapparent, the invention consists in general of certain novel features ofconstruction, combinations of parts and arrangements of elementshereinafter fully described, illustrated in the accompanying drawingsand specifically claimed.

In the accompanying drawings like characters of reference indicate. likeparts in the several views, and

Figure 1 is a transverse section through a furnace constructed inaccordance with this invention, the section being taken on the line 1-1of Fig. 2.

Fig. 2 is a section on the line 2-2 of Fig. 1.

Fig. 3 is an end view of one of the resister elements.

Fig. 1 is a side view of a portion of one of said elements. Fig. 5 is aside view of the furnace showing one of the supports on which it ismounted, the other support being removed.

In the embodiment of the invention herein illustrated, and which is tobe taken as merely typical of various embodiments of which the inventionis capable, a circular furnace is disclosed having a base plate 10whereon is mounted a circular series of segmental blocks 11 supporting acover plate 12 having a centrally disposed opening concentric with thefurnace and normally closed by a cover 13. j 7

These parts are all formed of some suitable material sufiicientlyrefractory to stand the maximum heat to be used and the parts arecemented, luted or otherwise suitably secured together so that thefurnace as a whole may be manipulated by means of a handle 13. Moreover,it is preferred to support the furnace rotatably on a pair of standards,one of which may be seen at 14 face of the wall of which is circular insection. Positioned against this inner wall surface are the resisterelements 16, which are usually, though not necessarily, formed ofcarbon. Each of these elements consists of a corrugated and taperedwedge, the construction being equivalent to a series of circular rodsdecreasingly graduated in diameter from the outermost inward and unitedby short necks or webs. The sizes of these rod portions are so graduatedthat, when the parts are-assembled as shown in Fig. 1, the differentsizes form arcuate series, the rod portions of each series being inclose contact so that current can flow through the several series. Inorder to provide current to the resister terminal, blocks 17 areemployed which may be moved by hand screws 18 to effect desiredcompression of the series of resister elements and thus enable thecurrent amperage flowing through the resister to be regulated. From thispeculiar arrangement and the shape of the resister elements it will beseen that, in effect, a series of paths is provided through the resisterfor the current flow and that the inner path is the shortest, so that,under the usual laws of multiple circuits, a greater current will flowthrough the inner ends of the resister elements than through the rest ofsaid elements, the resistance increasing and the current consequentlydecreasing outwardly. Thus the heating effect is concentrated about thecenter of the furnace by this novel arrangement.

From the terminals 17 extend wires 19 to a transformer (not shown),either air, oil or otherwise cooled and which forms an integral part ofthe furnace, although it is preferably not attached thereto. Thistransformer may be of any suitable type such as is now on the market,and on this account is not here illustrated. A suitable form could be anair cooled transformer having a primary voltage of say 110 volts andsecondary voltages of say 15, 20 and 25 volts. An adjustable switch canbe used to connect any one of the secondary voltages to the furnace sothat with the regulators 18 the temperature can be controlled within thewidest limits as set forth in the stated objects of the inventionaforesaid.

There has thus been provided a novel and efiicient furnace fullyaccomplishing the objects set forth.

Having thus described the invention, what is claimed as new is:

1. A furnace of the class described having a resister provided withcurrent paths in parallel decreasing in length from the outsideinwardly.

2. A furnace of the class described having a. resister consisting of aseries of arcuately' arranged wedge shaped elements, said elementscontacting each to each at intervals of their confronting faces. V

3. A resister element in the form of a blunt wedge corrugated on itssides parallel to its base.

at. A resister element formed of a series of integrally united circularrods graduated regularly in size to form a generally wedgeshapedstructure.

5. A resister consisting of a series of resister elements in arcuatearrangement and contacting at spaced intervals transverse the arc toform a plurality of arcuate current paths.

6. The combination with an electric furnace having a series ofcontacting resister elements therein, and means to adjustably press saidelements together, of a transformer having a plurality of graduatedsecondaries, and selective means for connecting said secondaries and theresister.

In testimony whereof I aflix my signature.

RAYMOND SAMUEL WILE.

